Dielectric properties and model food application of tylose water pastes during microwave thawing and heating

• Dielectric properties of tylose were measured over 300–3000 MHz and −30 to +60 °C.
• The effects of added salt (NaCl) on dielectric behavior were analyzed.
• Addition of salt increases the non-uniformity through reduction in penetration depth.
• Addition of salt develops a salty shield quickly and increases the thawing time.
• Lean tuna was satisfactorily simulated using tylose paste with 0.5% added NaCl.

The dielectric properties of tylose water pastes during microwave thawing and heating were measured over 300–3000 MHz and −30 to +60 °C, and the feasibility of their use as a frozen model food instead of frozen lean tuna was evaluated. The effects of salt (NaCl) content (0.5–2.0%, wb) on the dielectric properties were investigated. Although salt is a good additive for increasing the dielectric loss factor, higher salt addition increased the thawing time and non-uniformity through decreased penetration depth. A similar response to increasing temperature between frozen lean tuna and tylose paste was observed during MW thawing and heating at 2450 MHz, due to similarities in penetration depth. This was possible by an appropriate adjustment of the dielectric properties of tylose by salt addition (0.5% NaCl). This study confirmed the potential of frozen tylose paste as a model food in evaluating performance of microwave thawing of real foods.